Development of chemically-modified carboxymethylcellulose coatings for paper application

The present thesis work aims to obtaining a cellulose-based coating to be applied on paper in order to improve its barrier properties to moisture.In the first part of the work carboxymethyl cellulose sodium salt (CMC)has been grafted with different amines (octylamine, benzylamine, phenethylamine) in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methyl-morpholinium chloride (DMTMM) as a condensing agent in water at room temperature in order to obtain amidated carboxymethylcellulose derivates (CMCa). Different molar ratio anhydroglucose unit (AGUTOT)/DMTMM/amine have been tested to evaluate the substitution degree (DS) by 1H NMR studies. In the second part of the work, CMC-a films were obtained by casting and an in-depth study was carried out in order to evaluate the impact of DS and the nature of the amine on the functional properties of CMC-a (moisture content, moisture uptake, water vapor permeability WVP, UV-shielding). Furthermore, thermal analysis were performed (DSC and TGA) for evaluating the impact of the grafting on the thermal stability of CMCa In the third part of the work, three CMCa with the highest DS were tested in their final application: a 2 wt% solution of CMCa in water has been used as coating on filter paper by applying bar-coating technology. The WVP of coated papers was finally measured in order to optimize the bar coating process as function of CMCa layer to be applied aiming at improving the barrier properties of the paper.